Definition
A Just-In-Time (JIT) channel is one that a Lightning Service Provider opens in direct response to an incoming payment destined for a user who has no suitable channel yet. Instead of the user buying a channel, waiting for it to confirm, and then funding it, all of those steps collapse into one: the inbound payment triggers the channel open, and the funds flow through to the recipient in seconds. JIT channels exist to remove the cold-start problem that otherwise blocks brand-new users from receiving over Lightning.
How it works in practice
When a payment arrives at the provider headed for a channel-less client, the provider opens a new channel to that client and forwards the payment through it, deducting a fee. The client instantly gains both inbound and outbound liquidity, having never pre-committed capital. The behaviour is standardized as LSPS2 (bLIP-52) so that wallets and providers from different vendors interoperate.
Why it matters for onboarding
JIT channels dramatically lower the barrier to entry: a fresh wallet can receive its first sats without the user understanding liquidity at all. The trade-off is reliance on a service provider for the open, and a fee taken from the first inbound payment. For sovereignty-minded users this is a convenience layer, not custody, since the resulting channel is a normal non-custodial Lightning channel the user controls.
The JIT open establishes an ordinary payment channel once it confirms, and the inbound funds settle through the conditional contracts described in our HTLC entry.
In Simple Terms
A Just-In-Time (JIT) channel is one that a Lightning Service Provider opens in direct response to an incoming payment destined for a user who has…